Solid electrolytic condensers are widely used for charge accumulation in power supply circuits or noise cancellation in direct current. FIG. 16 shows an example of conventional solid electrolytic condensers (see Japanese Laid-Open Publication No. 2001-110688). The solid electrolytic condenser X shown in FIG. 16 has a structure where a dielectric layer 92, a solid electrolytic layer 93 and an anode conductor layer 94 are stacked on a porous sintered body 91 made of valve action metals such as tantalum. The porous sintered body 91 is obtained by press-molding e.g., fine tantalum powders and then sintering the molded body and has many micropores. FIG. 16 schematically shows the sintered state of fine valve action metal powders where micropores are formed. The dielectric layer 92 may be formed by anodizing the porous sintered body 91 and covers the porous sintered body 91. The solid electrolytic layer 93 is formed to fill in the micropores and covers the dielectric layer 92 all over. The anode conductor layer 94 may have a graphite layer and an Ag layer stacked together, and is joined to the surface of the solid electrolytic layer 93. For the materials of the solid electrolytic layer 93, manganese dioxide or conductive polymers are mainly used.
However, using manganese dioxide as the material for the solid electrolytic layer 93 is problematic in that the equivalent series resistance (hereinafter, ESR) of the solid electrolytic condenser X becomes relatively high. In the meantime, using conductive polymers such as poly(3,4-ethylenedioxythiophene) (PEDT) as the material for the solid electrolytic layer 93 is advantageous for reducing ESR, but is problematic in that heat resistance becomes as low as 125° C. Thus, it was previously difficult to provide a solid electrolytic condenser X having reduced ESR, as well as increased heat resistance.